Method of making an inner tube for tires.



H. 05c. METHOD OF MAKING AN INNER TUBE FOR TIRES. APPLICATION FILED DEC 30, 19I4- Patented Dec. 19, 1916.

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HENRY DECH, or TRENTON, NEW JERSEY, ASSIGNOR T0 MERCER-TIRE COMPANY, or TBENTON, NEW JERSEY, A CORPORATION or NEW JE SEY.

METHOD 0E MAKING An INNER TUBE FOR TIRES.

This invention relates to inner'tubes for pneumatic vehicle tires and to the method of making the same, with the object mview of providing an article of this character which may be expeditiously and cheaply manufactured in circular form and without any splice or other joint therein. It has been customary heretofore to manufacture these inner tubes by building them up on astraight pole andwrapping them spirally with cloth; after which, the tube was vulcanized in this position. At the end of vulcanization, the wrapper was removed, the tube stripped from the pole, its ends telescoped and secured in that form, by cementing or in some other convenient way. The making of the splice involves a considerable amount of labor and increases the opportunities for the production of defective tubes. Furthermore, when the tube is made in straight form, and, after vulcanization, bent into annular form, there is an unequal strain in the rubber in the various parts of the tube. This is also a disadvantage. By my invention the tube is manufactured in its final form on an annular mandrel which is subsequently removed through the slitprovided for the insertion of the valve.

A practical embodiment of one form of apparatus which may be used in carrying out my invention is shown in the accompanying drawings, in which,

Flgure 1 represents a. side view, partly broken away, showing the tube built up ona mandrel and wrapped; a portion of the mandrel being shown in withdrawn positlon Ill dotted lines. Fig. 2 represents an enlarged detail section showing a portion of the mandrel with the tube thereon. Fig. 3-

the tube, showing the slit therein.

Specification of Letters Patent. Patented Dec, 19, 1916.,

Application filed December 30, 1914. Serial No. 879,701.

The mandrel is annular in form and circular in cross section, and comprises two parts denoted respectively by 1 and 2. The part 1 is almost completely circular, but has the smaller section 2 severed therefrom. The section 2 is slightly tapered outwardly in order to facilitate its withdrawal inwardly. This section is shown as hollow but provided with solid ends 3, which have splines 4 secured to their faces by means of screws 5. These splines 4 are fitted to slide in keyways 6 formed in the solid ends 7 of the portion 1. It will be noted that the keyways only extend part way across the faces of the ends 7, so that the ends of the splines 4 may abut against the outer walls of the saidkeyways and thus prevent further outward movement of the section 2.

When the section 2 is in the position just described and shown in Figs. 1 and 2, it may be firmly locked in place by means of the set screw 8, which is adapted to fit in a hole drilled and tapped at one junction of the parts 1 and 2, as clearly shown in Fig. 1.

In manufacturing the tube, the section 2 is secured in the section 1 as just described, in order to form a circular mandrel. On this mandrel the tube 9 is built up in the usual manner and of the usual material. After the tube has been built, the whole is wrapped spirally and in an annular course by a wrapping of muslin or other appropriate fabric 10, in a manner well understood in the art. to a suitable heat for a suitable length of time, in order to properly vulcanize the tube; the details of which are well known and within the knowledge and skill of the art. After vulcanization, the wrapper 10 is removed. When the wrapper 10 has been removed, the inner periphery of the tube is slit, as indicated at 11,at a point opposite the section 2, and for a distance slightly greater than the length of the said section. This slit is preferably made by punching two holes 12, 13. in the tube, the desired distance apart, and then cutting the tube from one hole to the other. These holes provide rounded ends for the slit, which permits it to be freely stretched without danger of tearing. The cut is zigzag in form,as shown in Fig. 5. in order that the edges of the slit may dovetail into each other when reunited. The set screw 8 is then removed and the section 2 withdrawn inwardly through the This assembly is then submitted slit 11, as indicated in dotted lines in Fig. 1. The operator then takes hold of the tireand draws it peripherally around the part 1,. as indicated in F ig.4. In starting this operation, the tube is distorted'so asto causeone end of the part '1 to stick through the slit 11. A continuance of this peripheral movement of the tube on the part 1 will, as will readily'be seen, result in the entire part 1 passing out through the slit 11; or, in other words, result in the tube being drawn off from the said part 1. The next step consists in providing the valve for the tube, which may be secured, in the customary manner, in the slit 11, with the usual cemented patches and inner and outer plates; all of which is well understood and usually resorted to in the ordinary {ways of ma-nu-' facturing these inner tubes. In securing the valve in place, the dovetailed edges of theslit 11 are carefully fitted together; thereby assisting in the firm sealing of the sit. r

, It will be seen from the above that the tube is manufactured in the form desired mosses a my invention, and hence I do not intend to be limited to the specific details herein shown and described, exceptlasthey may be 40 included in the claims.

" -What I claim is:

v 1. The method of making an endless inner tube forpneumatic tires, compr sing, ,fi rst, forming the tube on a circular, sectlonal mandrel; second, Wrapping the tube and mandrel with fabric; third, vulcanizing the tube; fourth, slittingthe tube for the inset tion of the valve; fifth, withdrawing asection of-the mandrel throughthe said slit; sixth, drawing the tube peripherally off the remainder of the mandrel; and seventh,- fitting. a valve in said slit. v a

2. The method of making an endless-innertube for pneumatic tires, comprising first, forming the tube on a circular, sectional mandrel; second, Wrapping the tube and mandrel with fabric; third, vulcanizing-the tube; fourth, makingua round-ended zigzag? slit in the tube ,for'the'insertion of the valve fifth, withdrawing a section. of the mandrel through the said slit; sixth, drawing the i tube peripherally over the remainder of the mandrel; and, seventh, fitting-a valvein the said slit. 4 j '65 In testimony, that I claim the foregoing as my invention, I have signed my name 'in a presence of two witnesses, this sixteenth dayof December 1914.

Witnesses: F. GEORGE BARRY,

HENRY C.- TI-ILEME.

y HENRY nEoH-f;

Copies of this patent may be obtained for five cents each, by addressing "the Commissioner of Patents,

Washinztoml). G." 

